Antibiotics for honey bees- boon or bane?

It has now come to light that a widely used bee antibiotic may harm rather than help. This new study could well be an answer to colony collapse disorder. Honey bee populations have been mysteriously falling for at least five years in the United States, but the cause of so-called colony collapse disorder has largely remained unknown.

In a report published November 2 in the online journal PLoS ONE, researchers report that a widely used in-hive medication may make bees more susceptible to toxicity of commonly used pesticides, and that this interaction may be at least partially responsible for the continuing honey bee population loss.

Researchers at the University of Maryland write that “Despite considerable effort, no single cause of the phenomenon called colony collapse disorder (CCD) has been identified, though associations of several pathogens and parasites appear to increase the risk of colony collapse.”

Pathogens such as the destructive bacterial infection, American Foulbrood Disease often require the use of antibiotics or bee populations will be wiped out. Led by David Hawthorne of University of Maryland, the researchers pretreated healthy honey bees with the antibiotic oxytetracycline, and then exposed the bees to two pesticides that are commonly used in bee hives to control parasitic varroa mites. In both cases, the pretreated bees were much more sensitive to pesticide exposure than were bees that had not been treated.

The researchers suspected that oxytetracycline might interact with specific bee proteins called multiple drug resistance (MDR) transporters, making them less effective and therefore rendering the bee more at risk to the pesticides. To test this hypothesis, they pretreated the bees with another drug, verapamil, which is known to inhibit a particular MDR transporter. These insects showed increased sensitivity to five different pesticides, supporting the group's theory that MDR transporters, and specific combinations of independently safe chemicals, may play an important role in CCD.

Its worth noting that in India, there is a confusion about the recommendation of antibiotics for honey bees. While the All India Coordinated Project on Honey Bees recommends no antibiotics for honey bees, a few agriculture universities recommend oxytetracycline. But what is worrying is that beekeepers use these antibiotics irrespective of whether the hives are infested with mites or bacteria and whether they have been recommended at all.